mirror_zfs/module/os/linux/zfs
Matthew Ahrens e59a377a8f
filesystem_limit/snapshot_limit is incorrectly enforced against root
The filesystem_limit and snapshot_limit properties limit the number of
filesystems or snapshots that can be created below this dataset.
According to the manpage, "The limit is not enforced if the user is
allowed to change the limit."  Two types of users are allowed to change
the limit:

1. Those that have been delegated the `filesystem_limit` or
`snapshot_limit` permission, e.g. with
`zfs allow USER filesystem_limit DATASET`.  This works properly.

2. A user with elevated system privileges (e.g. root).  This does not
work - the root user will incorrectly get an error when trying to create
a snapshot/filesystem, if it exceeds the `_limit` property.

The problem is that `priv_policy_ns()` does not work if the `cred_t` is
not that of the current process.  This happens when
`dsl_enforce_ds_ss_limits()` is called in syncing context (as part of a
sync task's check func) to determine the permissions of the
corresponding user process.

This commit fixes the issue by passing the `task_struct` (typedef'ed as
a `proc_t`) to syncing context, and then using `has_capability()` to
determine if that process is privileged.  Note that we still need to
pass the `cred_t` to syncing context so that we can check if the user
was delegated this permission with `zfs allow`.

This problem only impacts Linux.  Wrappers are added to FreeBSD but it
continues to use `priv_check_cred()`, which works on arbitrary `cred_t`.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #8226
Closes #10545
2020-07-11 17:18:02 -07:00
..
abd_os.c Add abd_cache_reap_now for abd_chunk_cache users 2020-06-17 21:44:13 -07:00
arc_os.c Clean up OS-specific ARC and kmem code 2020-06-29 09:01:07 -07:00
Makefile.in Cleanup linux module kbuild files 2020-06-10 09:24:15 -07:00
mmp_os.c Add zfs_multihost_interval tunable handler for FreeBSD 2020-06-23 13:32:42 -07:00
policy.c filesystem_limit/snapshot_limit is incorrectly enforced against root 2020-07-11 17:18:02 -07:00
qat_compress.c Fix QAT allocation failure return value 2020-01-06 11:17:53 -08:00
qat_crypt.c QAT related bug fixes 2019-09-12 13:33:44 -07:00
qat.c QAT related bug fixes 2019-09-12 13:33:44 -07:00
spa_misc_os.c Make spa_history_zone platform-dependent in kernel 2020-03-02 09:43:30 -08:00
spa_stats.c Mark functions as static 2020-06-18 12:20:38 -07:00
trace.c Enable use of DTRACE_PROBE* macros in "spl" module 2019-11-01 13:13:43 -07:00
vdev_disk.c Make struct vdev_disk_t be platform private 2020-06-16 11:43:33 -07:00
vdev_file.c Mark Linux fallocate extensions as specific to Linux 2019-11-30 15:40:22 -08:00
zfs_acl.c Mark functions as static 2020-06-18 12:20:38 -07:00
zfs_ctldir.c Eliminate Linux specific inode usage from common code 2019-12-11 11:53:57 -08:00
zfs_debug.c Linux 5.6 compat: time_t 2020-02-27 09:31:02 -08:00
zfs_dir.c Add 'zfs wait' command 2020-04-01 10:02:06 -07:00
zfs_file_os.c Re-share zfsdev_getminor and zfs_onexit_fd_hold 2020-02-28 14:50:32 -08:00
zfs_ioctl_os.c Restore support for in-kernel ZFS ioctls 2020-06-08 13:57:22 -07:00
zfs_sysfs.c Persistent L2ARC 2020-04-10 10:33:35 -07:00
zfs_vfsops.c Mark functions as static 2020-06-18 12:20:38 -07:00
zfs_vnops.c Remove dead code 2020-06-18 12:21:18 -07:00
zfs_znode.c Mark functions as static 2020-06-18 12:20:38 -07:00
zio_crypt.c Linux 4.14, 4.19, 5.0+ compat: SIMD save/restore 2019-10-24 10:17:33 -07:00
zpl_ctldir.c Eliminate Linux specific inode usage from common code 2019-12-11 11:53:57 -08:00
zpl_export.c Eliminate Linux specific inode usage from common code 2019-12-11 11:53:57 -08:00
zpl_file.c Mark functions as static 2020-06-18 12:20:38 -07:00
zpl_inode.c Mark functions as static 2020-06-18 12:20:38 -07:00
zpl_super.c linux: add basic fallocate(mode=0/2) compatibility 2020-06-18 11:22:11 -07:00
zpl_xattr.c Mark functions as static 2020-06-18 12:20:38 -07:00
zvol_os.c Remove dead code 2020-06-18 12:21:18 -07:00